(a) Technical Field
The present invention relates to an electromechanical brake device and a method of controlling the same, more particularly, to an electromechanical brake device capable of estimating motor characteristics, and a method capable of controlling the electromechanical brake device by estimating the motor characteristics.
(b) Description of the Related Art
In general, a brake device for a vehicle is a device that generates braking force for decelerating or stopping a moving vehicle or maintaining the vehicle in a stopped state, and the braking is carried out while kinetic energy of the vehicle is converted into thermal energy by mechanical friction when the vehicle decelerates and frictional heat is radiated into the atmosphere.
As the brake device for a vehicle, there are a drum type hydraulic brake, a disc type hydraulic brake, and the like, and the disc type hydraulic brake obtains braking force by strongly pressing friction pads against both surfaces of a disc, which rotates together with a wheel, instead of using a drum.
However, the hydraulic brake has a complicated structure because it requires mechanical elements connected to a brake pedal in front of a driver seat, hydraulic piping, elements for controlling hydraulic pressure, and the like.
Therefore, an electromechanical brake (EMB) has been developed and used to simplify a configuration of the brake device.
The electromechanical brake has been developed to be used as an electronic parking brake (EPB), but recently, a field of the electromechanical brake has been expanded such that the electromechanical brake is used as a main brake that substitutes for the hydraulic brake in the related art.
Unlike the typical hydraulic brake, the electromechanical brake refers to a brake device that obtains braking force by pressing a friction pad by using a mechanical mechanism driven by an electric motor.
That is, the electromechanical brake has an actuator including the electric motor that rotates forward and backward in order to perform the braking operation and release the braking operation, and the electromechanical brake operates to press the friction pad using rotational force of the motor so that the friction pad presses the disc (causes friction with the disc) at a time of performing the braking operation.
Compared to the hydraulic brake, the electromechanical brake has a simple structure and a high response speed, and may be more precisely controlled, thereby improving braking safety.
The electromechanical brake is advantageous because braking force is easily controlled, and needs to be essentially applied to implement a brake-by-wire (BBW) system.
Meanwhile, the electromechanical brake is operated by various sensors and electrical devices without being mechanically connected with a driver, and as a result, it is necessarily required to ensure stability against a breakdown of the devices.
For example, a force sensor may be installed in the electromechanical brake, and the force sensor detects a clamping force which is the force with which a piston and a finger portion of a caliper housing press both surfaces of a disc through friction pads.
The electromechanical brake equipped with the force sensor controls torque output of a motor by using a clamping force detection value as feedback information so as to generate desired clamping force and braking force.
However, at the time of a breakdown of the force sensor, it is impossible to detect the clamping force, and as a result, motor torque control and braking force control, which use the clamping force detection value, also cannot be determined.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.